Update lifecycle from v0.20.16 to v0.20.18 (#843)

Release notes:
https://github.com/buildpacks/lifecycle/releases/tag/v0.20.18

Full changelog:
buildpacks/lifecycle@v0.20.16...v0.20.18

Co-authored-by: heroku-linguist[bot] <136119646+heroku-linguist[bot]@users.noreply.github.com>

Author: heroku-linguist[bot]

README.md

@@ -19,8 +19,8 @@ in each base image, see [this Dev Center article](https://devcenter.heroku.com/a
 | Builder Image                     | OS           | Supported Architectures | Default Run Image                   | Lifecycle Version | Status      |
 |-----------------------------------|--------------|-------------------------|-------------------------------------|-------------------|-------------|
 | [heroku/builder:20][builder-tags] | Ubuntu 20.04 | AMD64                   | [heroku/heroku:20-cnb][heroku-tags] | 0.20.11            | End-of-life |
-| [heroku/builder:22][builder-tags] | Ubuntu 22.04 | AMD64                   | [heroku/heroku:22-cnb][heroku-tags] | 0.20.16            | Available   |
-| [heroku/builder:24][builder-tags] | Ubuntu 24.04 | AMD64 + ARM64           | [heroku/heroku:24][heroku-tags]     | 0.20.16            | Recommended |
+| [heroku/builder:22][builder-tags] | Ubuntu 22.04 | AMD64                   | [heroku/heroku:22-cnb][heroku-tags] | 0.20.18            | Available   |
+| [heroku/builder:24][builder-tags] | Ubuntu 24.04 | AMD64 + ARM64           | [heroku/heroku:24][heroku-tags]     | 0.20.18            | Recommended |
 
 The builder images above include buildpack support for the following languages: Go, Java, Node.js, PHP, Python, Ruby & Scala.
 Additionally, `heroku/builder:22` and `heroku/builder:24` includes buildpack support for .NET applications.

builder-22/builder.toml

@@ -15,7 +15,7 @@ image = "docker.io/heroku/heroku:22-cnb"
 mirrors = ["public.ecr.aws/heroku/heroku:22-cnb"]
 
 [lifecycle]
-version = "0.20.16"
+version = "0.20.18"
 
 [[buildpacks]]
   id = "heroku/deb-packages"

builder-24/builder.toml

@@ -7,7 +7,7 @@ run-image = "docker.io/heroku/heroku:24"
 run-image-mirrors = ["public.ecr.aws/heroku/heroku:24"]
 
 [lifecycle]
-version = "0.20.16"
+version = "0.20.18"
 
 [build]
 image = "docker.io/heroku/heroku:24-build"